Tuning device



Patented. oef; 31, 1939 PATE-NT oFFicr-i TUNING DEVICE William G. Wheat, Kansas City, Mo., assigner ot one-fourth to Dwlghtoberts and one-fourth' toJoseph N. Minime, both of i Applicationliebrnary 1, 1937, Serial No. 123,317

' 'i claims. (ci. 'r4-fio) of large mass, and a tuning shaft for acon- My invention relates to circuit tuning devices, f

and more particularly to means for tuning an electrical circuit, such'as a radin circuit, or cir- The principal ypurpose 'of my invention isv tov provide a tuning device comprising one or more condensers, or similar members, made up oi stan which said movable and stationary means are Iii interposed, and means for yadjusting said movabe means relative to the stationary means, comprising weighted means, or means of relatively large mass, for causing the continued movement of the movable means relative to the stationary means after such movement has been initiated by the operation of means rotating the weighted means, or member of large mass.

This may be referred to as a free wheeling tuning mecha'- nism, in that the weighted means, or means of large mass, after being started, will continue to rotate the parts due to the inertia of the member of large mass tending to continue such rotation,

and because my improved apparatus comprisesv means, -whereby, if said movable members, or

movable means, associatedy with the stationaryl means to control the tuning of the circuit, or circuits, in which said movable means and stationary means are interposed, reaches the limit of its movement in either directiol I, the rotatable means of large mass will Icontinue its rotation without moving the movable means interposed in the circuit, thus preventing any damage to such movable means. l

y More particularly my invention comprises means for tuning a variable condenser, or other adjustable means, for tuning a circuit, comprising a tuning shalt associated with the rotor, orrotors, of the condensers, or similar variable means, and rotatable means that is possessed of a large amount of inertia, which is provided with means .for setting the same into rotative motion, rand which is provided with means connecting the samewith the tuning shaft to set the tuning shaft into rotation, but at a speed of rotation that is less than the speed of i rotation of the means of relatively large. inertia; This' is accomplished by some spe'ed reduction driving means,l a worm drive being' preferred, but other driving means, suchtas belt drives, or reduction gears of various sorts being usable.

More particularly my invention comprises such n speed reduction driving means between rotatable means of high inertia, such as a rotatable member denser, or gangs of condensers, or similar. adjustable variable means for tuning a-circuit, or cii'- cuits, and a spring clutch mechanism, which.

permitsthe rotation of the means of large inertia to continue, if the rotation of the timing shait. or the adjustable circuit" tuning means associated therewith, is positively halted by some means, such as a limiting stop. i

One of the principal advantages of my invention is that with a circuit tuning apparatus, such as I have provided, the dial which is `usually associated with the tuning shaft,- and said tuning shaft and the adjustable circuit tuning means rotating with said shaft, can be rotated much more steadily than is possible-by direct rotation oi the ordinary tuning shaft by hand, and the .I

rotation thereof Vby my improved means can be halted at a desired point by an unskilled operator much more accurately than is possible with a tuning shaft vthat is rotated by such an unskilled operator by direct hand operated means carried by the tuning shaft itself,A or by means geared to the tuning shaft and rotated by the l operator at a higher speed than the tuning shaft. The operation of such a geared driving means,

Vor other speed reduction means, from ahand wheel, or some other means,`that is rotatable by the operator, to drive a tuning shaft, is very tedious and due tothe fact that the rotatable operating member has to be rotated over a `considerable arc to cause any eiect on the tuning, the impatience of the operator tends to eliminate any advantage that is gained by the speed reduction drive between the tuning shaft and said operating means, unless my invention is applied thereto, whereby the member of relatively large mass provides an inertia device, which is readily set in rotation by the operator and continues the rotation of the parts, including the drive between -said rotatable operating means, or other operat' ing means, for manual operation of the device and the tuning shaft, thus causing the operator of the device to devote his attention mainly to the dial indicating the position of the movable means, such as the rotor plates of the condens-` ers that are used for tuning the circuit, and

enabling the operator to stop the rotation of the tuning shaftlvery accurately by merely engaging his hand with the operating means to stop'the `"rotation of the inertia means, such as a ywheellike member of large mass, having its centerof mass on its axis of rotation. Such a member that has its center in mass of its axis of rotation, or substantially in its axis of rotation, will provide a uniform, or substantially uniform, rotation of parts, particularly where a speed reduction drive means is provided, no matter what position of the condenser plates of the rotor, or rotors, of the apparatus may have.

Other objects and advantages of my invention will. appear as the description of the drawing proceeds. I desire to have it understood,how ever, that I do not intend to limit myself to the particular details shown or as defined in the claims. A

In the drawing:

Fig. l is a fragmentary view partly in elevation and partly in section, showing my improved tuning apparatus.

Fig. 2 is a fragmentary view, similar to Fig. 1, showing a modication of my improved tuning apparatus.

Fig. 3 is a fragmentary View partly in'vertical section and partly in elevation of a further modiiication.

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 1.

Fig. 5 is a fragmentary section taken substantially on the line 5-5 o'f Fig. 3.

Fig. 6 `is an enlarged fragmentary front elevational view of the guiding means for the actuating member in Fig. 3, the actuating member and arm being omitted, and

Fig. 'I is a fragmentary view partly in vertical section and partly in elevation, of a further modiflcation of my invention.

Referring in detail to the drawing, my tuning apparatus is shown as being mounted in a casing, or cabinet, such as is commonlyl used for radio apparatus, having a bottom wall I and a front wall II, a base member I2 being secured to the bottom wall Ill. Said base member I2 is provided with an upstanding bracket I3 carrying a housing I4 constituting a shield for the stationary plates, or stator members, I 5 of a plurality of condensers. A shaft I6 is mounted in the upstanding end walls II and I8 'of the shield, or casing, I4 for rotation therein, any suitable bearings being provided for said shaft. The rotor members having the plates I9 are mounted in fixed position on said shaft to rotate therewith so Ithat said rotor plates will move into cooperative relation to the stator plates I5 to progressively vary the capacity of the condensers thus formed, in a well known manner. Said condensers are interposed in electrical circuits by connection of the respective stator and rotor plates therein. Each group of stator plates I5' is, of course, insulated from the other groups in the usual manner. Any suitable mounting for the stator plates may be used, such as the b'ar 20 extending between the endymembers II and I 3, which issecured therein, and which is provided with sleeve-like insulating means 2| surrounding the same to insulate the plates I5 from the bar 20. It is, of course, to'be understood that the stator and rotor plates can be mounted in any desired conventional manner, as is well known, to obtain the desired relative adjustment and desired capacity relation thereof to produce the desired tuning effect on the circuits in which the same are located.

The shaft Iextends through a suitable opening in the front wall II and any indicating means, such as a dial, 22- is providedon said shaft to indicate the position of the rotormembers relative to the stator members.

@Mounted on the base member I2 is a frame having the trans'sbottom member 23, the upstanding side members 24 and a transverse top member 25. Depending from' the transverse described, except member 25 is a U-shaped bracket 2t having a transversely extending portion 2'I carrying a ball bearing 28 for the vertically extending shaft 29. 'I'he shaft 23 also extends through an ordinary bearing 30 in the transversely extending frame member 25. Secured to theend portion of thev shaft 29 in any suitable manner, as by means of a set screw 3 I, is the hub portion 32 of a hand wheel of large diameter 33 having the knurled, or roughened, edge portion 34, the peripheral edge portion 34 extending through a suitable opening in the front wall II below any suitable shield 35 therein, so Vas to project from the casing, or housing, forwheel, 33 is a weight 36, which may be made in any desired manner, but must be of such size and weight that with the Wheel 33, will constitute a rotating mass that is relatively large compared with the other moving parts of the apparatus, so that the inertia of said mass will create a momentum for the rotatable member 33 that will cause it to rotate for a Ylarge number of turns. after being given a start by engagement lwith the roughened operating edge portion 34 thereof by the lingers of the operator of the apparatus. The weight 36 should be so proportioned and so mounted on the member 33 that said member 33 and the Weight 36 will constitute a mass, the center of mass of which lies in the axis of the shaft 29, so that the rotation thereof will be uniform about said axis. The weight may be detachably connected to the wheel 33 by suitable securing elements 37.

The upper end of the shaft 29y extends through the bearing 30 and has a disk 38 fixed thereto to rotate therewith in any desired manner. A similar disk-like member 39 is mounted in cooperative relation thereto, being slidably mounted on a shaft 40, which is in axial alignment with the shaft 29 and which is mounted in a bearing 4I on the upstanding U-shaped bracket 42 provided on the vtransversely extending frame member 25. A hub 43 is provided on the disk 39 and a slot 44 is provided in the shaft 40, through which the pin 45 extends, which is mounted in the hub 43, as will be evident from Fig. 4. A collar 48 is fixed on the shaft in any suitable manner, as by means of a set screw, and a compression coil spring 4I is mounted between the collar 46 and the hub 43,

1 urging the disk 39 4into frictional engagement with the disk 38. It will be obvious that thetension of the spring 41 can be adjusted 'to get theuesired meshes with a larger gear 53 fixed on the shaft I3.

It will be evident that as the operating member 34 is set intorotation by the manual movement thereof, the large mass of the members 33 and 36 is set into rotation,'as well as the shaft 29, and the shafts 50 and I5 through the worm drive and the gear drive above referred to. Also 1t will be noted that after the large mass comprising the members g5 liti tilt and 3b is set into rotation, and the hand is disengaged from the rim 34 thereof by the operator, the mass will continue to rotate due to inertia thereof, continuing the rotation of the intermediate driving means and the shaft i6, thus continuing the rotation .of the dial 22 and the rotor members having the rotor plates i9, and that said shaft i9 and the rotor plates will move at a much slower rate of rotation than the shaft 29 and the large rotating mass moving therewith comprising the members 33 and 36.' As a result, all that is necessary to set the shaft i6 in operation is to give the rotatable member 83 a start, whereupon the parts will free wheel, or coast along, for a considerable interval, enabling the operator to put his full attention on the dial indicating the position, or the adjustment of the tuning apparatus, comprising the movable rotor plates.

iii)

dii

. parts.

The member iii can be turned at the exposed rim portion tt thereof as frequently as may be necessary to get the rotor members in approximately the desired adjustment and then the op-` erator can halt the movement of the shaft i6 and the rotor plates at the exact point desired by engagement of the iingers with the rim ttor the rotatable member tt, thus stopping the rotation of the shaft t9 and, through the wormwheel and gears, the shaft it substantially instantaneously, the parts associated with the clutch member 3d having such a relatively small mass and so little inertia that there will be no slippage of the clutch members tt and il@ under such circumstances In order to prevent any play, or bach lash, between the teeth of the gears ,utilized in the drive, the shaft-iii is provided with a coilspring tt, which is secured at one end to said shaft, and at the other end to a pin 5t on the end wail it. Should, however, the operator rotate the member tt continuously, or carelessly, to such an extent that he wili move the rotor members to the limit of their rotation so th'at these rotor members will engage stops customarily provided for limiting the movement thereof at opposite ends of the arc through which the same are adapted to move, to either obtain their maximum or minimum capacity relationship to thestator plates it, the friction clutch will operate to prevent any damage to any of the 'lihat is,the shaft it, the gears t2, tt, shaft 5d and shaft dit, and all the parts carried thereby, will stop, stopping the disk tti from rotation, whereupon the disk tt, will turn relative to the disk 39 without causing any rotation of the disk 39 due to the yielding engagement of said disks 38 and 3d 'through the spring t'fi. 0f course, the friction between themembers dit and 3d will act to some extent as a brake to reduce the amount of rotation that the member 9i will have.

iit is, of course, to be understood that any suitable` mounting and spacing means may be provided for the parts, such asthe spacing sleeve 9d between the gear 53 and the member ii and the sleeve b1 carrying the rotor plates Ji9, and any suitable means for centering the rotor plates relative .to the stators may be provided, such as the resilient means 58. Any suitable cover for the dial 22, such as the concavo-convex glass covering 59. may be provided, if desired.

Instead of providing Ithe actuating means directly on the rim of the rotatable member carryingthe weighted member and constituting part of the rotatable means of large mass, other actu-l ating means may be provided, such' as shown in Figs. 3 and 5. The base member i2 is provided with a bracket 69, which has a transversely extending portion GI having an vopening therein, in

which the sleeve 62 is mounted, which is provided with a groove 53. in which the yoke 84 is mounted.,

. means of a member 69 at the other side thereof,

which constitutes a pivot for an arm 61 extending through an opening in the front wall member il, and which has a finger piece 68 mounted thereon, which is recessed at 69 for engagement of a finger of the operator therewith to enable the operator to push downwardly on said member t8 and at thesarne time move the same laterally.

A spring 19 is provided, which normally presses upwardly on the arm d1 to holdthe friction block 1I, fixed thereto, away from the annular rib 12 provided on the rotatable member of large mass 13, said member 'it being fixed on the shaft 29 by any suitable means, such as the set screw 1t, a spacing collar 15 being provided on the shaft 29 between said member-.19 and the base member i2. It will be obvious that when the member 68 is pressed downwardly and moved laterally, thefriction block il, which may be made of any desired material, such as iiber, that would have a frictional engagement with the rib 12, is engaged with said rib and the arm t1 acts to rotate the rotatable member 1t and the shaft 29, the shaft 29 being connected with the shafts 50 and i8 in the same manner as previously described. However, as soon as the operator removes the fingers from the finger piece td the spring 10 will act to disengage the member 1i from the rib 12, permitting' continued free rotation of the member of large mass 'I3 and the parts connected therewith through the shaft 2d.

The member lli is provided with an upper shield, or guard, 1t and a lower shield, or guard, 11 located on opposite sides of the arm 61, these being curved, as will be obvious from Figs. 3 and 6, and provide a slot 'i8 between the same, in

which the arm `Gli operates. However, in order to prevent the engagement of the mem r 1| with the member .12 after said member 1 has been started by means of the finger piece 6,8, the upwardly directed edge portions '19 are providedon the lower'shield member 11, causing the arm 91 to ride up on the cam edges 19 thus formed, which shown in Fig. 1, 'other means fors driving the' tuning shaft from the rotatable means oi large mass, may befprovided. Thus in Fig. 2 a rotatable membergof large mass 8| havingits center of. -mass in the axis of the shaft 82, is shown, said shaft 82 being mounted in bearings on a U-shaped i bracket 83 provided on the front wall member I i and being provided with a knob 84 fixed thereto byl any suitable means, such as a setgscrew, or pin, which vs provided. with a roughened, milled, or knurled, edge 85, said member BI being fixed by a set screw, or other similar means, -t o the shaft 82 so that rotationl of the knob will rotate the weighted wheel, or rotatable .member of large mass 8|. A pulley 86 is also fixed to the shaft 82 to rotate therewith in any suitable manner, as by meansof a set screw 81, and a belt 88 operates oversaid pulley and 4over a pulley 89, which is rotatably mounted on the sleeve 96. said sleeve being rotatably mounted on the shaft I6'.

A collar 9|) is fixed to the sleeve 96 by means of a set screw 9| and a coil compression spring 93 engages with the hub @t of a friction disk clutch member St, which is slidably mounted on the sleeve 96 to rotate therewith, and which er1- gages with a clutch face 95 provided on the Pulley 89. The pulley titl will thus normally rotate with the shaft |36 unless the shaft 96 is stopped, whereupon the pulley et will rotate relative to the shaft due to the provision of the resilient friction disk clutch arrangement. A gear t? is fixed to the sleeve t6. The gear @l meshes with the gear 99 that is mounted on the shaft |99, the gear @El being appreciably larger than the gear til, and a gear lili being also provided on the shaft Hit, said shaft tilt being mounted in the end wall ll of the casing it, or in any other desired frame member, by any suitable means, such as a nut |02 engaging a 'screw-threaded end on said shaft, said shaft itil being stationary and the gears 99 and iti, which are, preferably, made integral with the sleeve portion It@ rotating on said shaft. The gear portion itl is, preferably, in the nature of a pinion, and meshes with a gear Hifi that is fixed on the shaft i6 by means of the set screw |05, or other similar means. The shaft it extends through the sleeve 96 and the hub of the gear It is spaced from the gear 96 by means of a spacing ring 98, and from the member il by means of a collar |06. The shaft I t has the rotatable indicator member, or dial member, 22 provided thereon, in the same manner las previously described, while the sleeve 96 has the dial or indicator member 22 mounted thereon to rotate therewith. Thus means is provided for indicating the rotation of both the sleeve 96 and the shaft i6 in this case. In order to provide the necessary tension on the belt, an idler pulley |01 is provided, engaging the-belt 88, which isimounted on an arm |08 mounted on a pivot member |09 and urged into engagement with the belt by means of the spring I I0 in a well known manner.

Ity will be obvious that as the member 84 is en-v gaged and twisted, or rotated, to rotate the member 8|, the pulley 86 and belt 88 will rotate the pulley 89, and through the sleeve 96 and the train of gears, the shaft i6', which shaft I6 will rotate at a very slow speed as compared with the shaft 82. This will continue until the limiting means stopping the rotation of the shaft I6 is engageddn the manner previously referred to in connection with Fig. 1, whereupon the friction clutch comprising the members 94 and 95 will cause the rotation of the sleeve 96 and the shaft I6 to be halted, although the pulley 89 and the member 8| will continue 'to rotate due to the fact that the inertia of the mass of the member 8| will continue such rotation.

In Fig. 7 a further modification is provided. -A shaft 82, which corresponds to the shaft 82 in Fig. 2, is mounted in a similar manner to that previously described, and the rotatable member of large mass 8| is xed to Said shaft 82 in a similar manner to that previously described. Also fixed on the shaft 82 to rotate therewith, is the pinion III, which meshes with the gear ||2, which also has a pinion H3, preferably, formed integral therewith, or mounted t0 rotate in unison therewith, which is mounted on a fixed shaft |I4 secured in any suitable manner to the front wall Il', a spacing sleeve ||5 being provided between said front wall and the hub of the gear H2. The

pinion I3 meshes with a gear H6, which has the friction dislr` provided thereon, corresponding to the dislr 95 shown in Fig. 2. The other parte shown in Fig. 7 are the same as previously clescribed in connection with Fig. 2 and are correspondingly numbered, the operation being substantially the same as previously described,.ex

rcept that the drive from the shaft t2 to the sleeve |36 is through gearing instead of by means It is of course,.to be understood, that in any form of the invention, the gear ratios, size oi' gears, size of pulleys, and so on, can be varied as may be desired-to obtain the desired speed reduction between the driving, or operating, shaft and the condenser, or tuning shaft, and that this can be utilized to obtain any fineness of reading of the dial, or adjustment of the condenser, or o ther tuning member, that may be nection between said driving shaft and tuning shaft, said driving connection comprising means permitting rotation of said driving shaft by the inertia of said member of large mass upon halting the rotation of said tuning shaft by said stop means and halting rotation of said tuning shaft by said manual means acting on said member of large mass to stop said member of large mass.

2,. Variable means for tuning an electric circuit, comprising stationary and movable elements interposed in said` circuit, means for mounting said elements in such relation to each other that the effect of said elements on said cir cuit will vary in accordance with the relative `position of said elements, a rotatable shaft connected with said movable element to move the same relative to said stationary element in proportion to the rotation of said shaft, and means for rotating said shaft comprising a rotatable element of large mass, a driving connection between said element of large mass and Said shaft, said driving connection permitting halting of said shaft without halting said element of large mass, but halting said`shaft upon halting rotation of said -element of large mass, the center of mass of said rotatable element of large mass lying substantially in the axis of rotation thereof, and means for manually controlling the amount of rotation of said element of large mass.

3. An apparatus of the character described comprising driven means including a tuning shaft, driving means including a driving shaft, a member of large mass mounted on `Said driving shaft to rotate therewith substantially about its center of mass, means for rotating said member of large mass and manually controlling the amount of rotation thereof and a driving connection between said driving shaft and tuning shaft, said driving connection comprising yielding clutch means, and the inertia of said driving means being much greater than that of the driven means.

' 4. An apparatus of the' character described Icomprising driven means including a tuning shaft, driving means including a driving shaft, a member of large mass mounted on said driving shai't to rotate therewith. substantially about its center of mass, means for rotating said member of large mass and manually controlling the amount of rotation thereof and a driving connection between said driving shaft and tuning shaft, said driving connection comprising means for rotating said tuning shaft at a much slower speed than said driving shaft, and including a.V

friction clutch having resilient means for holding said clutch in frictional engagement, the inertia of said driving means being much greater than that of the driven means.

5. Circuit tuning means comprising rotatably mounted tuning means. an indicator member indicating the position of said rotatably mounted tuning means, a manually rotatable operating member for initiating rotation oi said rotatable means, and a weighted member ot much greater mass than said rotatably mounted tuning means directly connected with said operating member to rotate about its center of mass in unison with and at the samey speed as said operating member, and extend the rotation of said rotatably mounted tuning means after release of said op- 25 erating member by the operator, and a slip driving connection between saidI rotatably mounted tuning means and said weighted member operating to instantaneously halt the extended rotation o! said tuning means upon halting rotation 30 of said operating member by manual engagement therewith Vby the operator upon said indicator member reaching a desired indication.

6. Circuit tuning means comprising rotatable means and stationary means having capacity relation to each other, means for indicating the position of said rotatable means, stops for 1imiting the rotation of said rotatable means, manual means for initiating rotation of said rotatable means, and rotatable inertia means' exing means tending the rotation of said rotatable means after manual initiation thereof, means positively connecting said manual means and said means for extending the rotation thereof and a slip driving connection-between said 'means for extending said rotation and said rotatable means, said connecting means cooperating to halt extended rotation of said rotatable means by engagement with said manual means at any indicated position thereof and by said stops at the limiting positions of said rotatable means during rotation of said inertia means.

7. Circuit tuning means comprising rotatably mounted tuning means, an indicator memberrotating with said rotatably mounted'tunin'g means. stops limiting the rotation of said rotatably mounted tuning means, a manually rotatable op-f erating memberl for initiating rotation ofsaid tuning means, and a weighted member of much greater mass than said rotatably mounted tundirectly connected with saidoperating member to rotate about its center of mass in unison with and at the same speed as said `operating member, and extend the rotation of said rotatably mounted tuning means after disengagement of said operating member by the operatoa,` and a slip driving connection between said weighted member and said rotatably mounted tuning means, Asaid driving connection operating `to instantaneously halt the extendedrotation of said tuningmeans upon halting rotation ofv said operating member under the control of the operator with said indicator member at a desired indication, and to permit rotation of said weighted means to proceed, upon limitation o! the rotation of said rotatably mounted tuning means by said stops.j

wmuam G, WHEAT.' 

